The present invention relates to an apparatus for stirring fluid, and more particularly, to an apparatus which can efficiently stir fluid in a tank, and a method for stirring fluid.
Conventionally, in case fluid, such as sludge, is introduced into a tank and is separated for treatment, an accelerating agent for separating fluid is added to the sludge while stirring blades disposed in the tank are agitating the sludge.
This apparatus includes a single tank. Thus, in case of processing high density fluid, if a setting angle for each stirring blade is large, a pressure resistance becomes high at rotation of the blades, so that a large amount of driving load is applied to a motor. Therefore, instead of forming the large setting angle for the blades, the stirring blades are rotated at a relatively high speed so as stir the high density fluid.
This prior apparatus has, however, following problems. Firstly, this apparatus is not suitable for a separation of the sludge, slurry or the like, a large amount of which is supplied, because it takes time for processing. Secondly, if a rectangular tank is used in this apparatus, turning flow is difficult to reach to the corner portions, especially to the corner portions at a bottom, because of the square corner portions. As a result, fluid at the corner is left unprocessed and a result from the process in a tank is undesirable. Therefore, in this prior apparatus, only a cylindrical tank can be used because the turning flow in such a cylindrical tank is satisfactory.
In order to obviate the foregoing problems, the object of the present invention is to provide an apparatus and a method for stirring fluid, wherein a large amount of fluid can be processed in a short period of time, and fluid can be stirred desirably and certainly even in a rectangular tank.
Further objects and advantages of the invention will be apparent from the following description of the invention.